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Jordan University of Science and Technology Microelecromechanical Systems Dr. Mohammad Kilani Announcement No class on Sunday, 12th of February The Mechanical Face of the Silicon Revolution Mechanical First silicon oscillating resonators Math Logic 1940 Bell lab develops the semiconductor transistor First silicon pressure sensor 1950 First Integrated Circuits Planar technology invented 1960 IBM patents silicon micronozzles for inkjet printing 1970 Commercial Integrated Circuits Microprocessor invented 64 Bit DRAM 64 Kbit DRAM Analog Devices commercializes MEMS airbag accelerometers 1980 1990 Texas Instruments demonstrate Digital Projection Display using digital mirrors 2000 1.2 million transistors on a chip 5 million transistor on a chip 50 MHZ processors 2.5 GHZ processors 4 MB DRAM 512 MB DRAM Characteristics of MEMS Devices • Mechanical functions • Micron-size features • Silicon based • Fabricated using IC fabrication technologies • Integrated with microelectronics • Weight, cost, size, accuracy and reliability Example Commercial MEMS Applications Inertia Measurement Devices Accelerometers: over 100 million sold since 1993 Vibration sensors Rate sensors (Gyroscopes) Example Commercial MEMS Applications Pressure Sensors Pressure sensors for industrial medical and other applications Example Commercial MEMS Applications Microfluidic Devices: Inkjet nozzle Microvalves Lab on a chip Chemical sensors Flow controllers. Example Commercial MEMS Applications Optical MEMS: Displays Optical switches All optical communication Adaptive optics (deformable mirrors) over 11,000 iterations per second was achieved Example Commercial MEMS Applications Cartridge Label Sample Entry Well Gasket Biomedical Application Fluid Channel Point of care diagnostics Cartridge Cover Minimally invasive devices Sample Entry Well Implantable devices Tape Gasket Biosensor Chips Calibrant Pouch Puncturing Barb Cartridge Base Air Bladder Not this … … But things that make it better MEMS Market 12 MEMS Sales 10 $ billion 8 Estimated Predicted 6 Source: Frost and Sullivan 4 2 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Photolithography (Photography with depth Mask Substrate Photolithography (Photography with depth Mask Photo resist Substrate Photolithography (Photography with depth UV Light Mask Photo resist Substrate Photolithography (Photography with depth UV Light Mask Photo resist Substrate Photolithography (Photography with depth Resulting pattern Bulk Micromachining Surface Micromachining Substrate Bulk Micromachining The exposed area on the substrate is subjected to further chemical etching Area protected from chemical etching Area exposed to further chemical etching Substrate Bulk micromachining Anisotropic etching Utilize the crystallographic structure of the silicon lattice Bulk micromachining Isotropic etching Attack the silicon substrate in all directions with equal rate Bulk micromachining • Large depths • Limited complexity • Piece by Piece fabrication • Manual assembly • Incompatible with IC tools and materials Surface micromachining • Photoresist is used to expose a sacrificial material, which is etch released at the end of the process • Exposed areas of the sacrificial material are used as anchors for an additional level of silicon (polysilicon) Deposit and pattern polysilicon film Etch release sacrificial SiO2 film Surface micromachining 20 microns • Planar • Complex structures with no manual assembly • Compatible with IC tools and materials 100 microns • Batch fabrication SUMMiT Layers 100 microns Surface micromachining • Became a standardized technology • An example is Sandia’s SUMMiT technology • Provides five levels of low stress polysilicon • Provides rotational freedom between P1 and P2 levels • Available design tools and components library P4, 2.25 microns LPCVD S4, 2.0 microns PECVD Dimple 4 gap 0.2 microns P3, 2.25 microns LPCVD Dimple 3 gap S3, 2.0 microns PECVD 0.4 microns P2, 1.5 microns S2, 0.3 microns P1, 1.0 microns Dimple 1 gap S1, 2.0 microns LPCVD 0.5 microns P0, 0.3 microns Silicon Nitride, 0.8 microns Thermal SiO2, 0.63 microns Substrate 6-inch wafer, <100> n-type SUMMiT Layers Sandia Microengine • Uses two two electrostatic comb drives • Uses two input signals for each comb drive and a ground signal • A mechanical linkage converts linear oscillation into continuous rotation at an output gear. • Output speeds up to onemillion rpm have been demonstrated 2 mm Microtransmission gear trains Micromirrors for Fiber Optics switching boards and digital displays Micropumps Micropumps Micropumps Systems Engineering Viewpoint Actual Output Desired Output Comparison Controller Measurement Process Systems Engineering Viewpoint Microelectronics Actual Output Desired Output Comparison Controller Measurement Process Systems Engineering Viewpoint Micromechatronics Actual Output Desired Output Comparison Controller Measurement Process Why we should teach MEMS in Jordan • Future Jordanian engineers must participate in developing novel, globally marketed, products. • MEMS is a relatively new field, with a prospect for a number of future innovation. Many products can be improved using MEMS and many other products can be innovated. • Complete MEMS development requires a huge investement in microfabrication infrastructure. However, very few companies do the A-Z in MEMS product development. MEMS development can be performed in design, new fabrication technologies, etc. Micromachines Applications in medical Diagnostics and Treatment Producing a Pin Joint Hub Time etch S1 to produce dimples and anchors Deposit and pattern P1. isotropic etch S1 produce undercut Conformal deposition and patterning of S2 Conformal deposition and patterning of P2 Deposit and pattern S3 and P3 Etch release to produce free standing gear 100 Up 75 Vo lta ge (V) Microsystem Testing 50 25 0 0 250 500 750 1000 500 750 1000 500 750 1000 750 1000 100 Probe Station Down 75 Vol tag e 50 (V) 25 0 0 250 100 Right Vol tag e (V) 75 50 25 0 0 250 100 Left Optical microscope Vol tag e (V) 75 50 25 0 Vacuume chuck 0 250 500 time(ms) Probe tip holder Micropositioner Ground Drive signal ports Up Right Down Left Applications Micropumps Photolithography (Integrated Circuits Fabrication) UV light Mask Photochemical reactions Photoresist Substrate Resist development Bulk Micromachining Surface Micromachining Microengineering: Designing, Building and Testing Microscopic Feature Devices Eight Legged Microrobot The out-of-plane rotation of the eight legs is obtained by thermal shrinkage of polyimide in V-grooves (PVG). Leg movements is obtained by sending heating pulses via integrated heaters causing the polyimide joints to expand. The size of the silicon legs is 1000x600x30 microns, and the overall chip size of the robot is 15x5x0.5 mm. The walking speed is 6 mm/s and the robot can carry 50 times its own weight World’s smallest helicopter contructed from parts made using LIGA process. With a length of 24 millimeters and a weight of 0.4 grams the helicopter takes off at 40,000 rpm. With a diameter of only 1.9 millimeters the electromagnetic motors can reach an incredible revolution speed of nearly half a million rpm on the one hand, and a considerable torque of 7.5 µNm on the other hand. 15 mm